# Private audio tools — trim, convert & transcribe, no upload

> Trim, normalize, convert and transcribe audio in your browser with FFmpeg and Whisper. Your audio files are never uploaded.

Audio Lab edits, cleans, and transcribes audio on your device using FFmpeg and on-device Whisper, so your recordings stay with you.

## Tools in this workspace

- [Trim & fade](https://www.safepaper.app/audio/trim-audio): Cut a clip to a start/end range and add fade-in / fade-out — all in your browser with FFmpeg.
- [Speed & pitch](https://www.safepaper.app/audio/tempo-pitch): Change tempo without affecting pitch, or shift pitch in semitones with formant preservation — locally, no upload.
- [Normalize (LUFS)](https://www.safepaper.app/audio/normalize-loudness): Normalize to a target LUFS with true-peak limiting (EBU R128 loudnorm) on your device.
- [Noise & hum](https://www.safepaper.app/audio/noise-reduction): Reduce hiss and mains hum with high-pass, low-pass, and FFmpeg's afftdn denoiser locally.
- [Silence trimmer](https://www.safepaper.app/audio/silence-trim): Strip leading/trailing silence and long gaps with FFmpeg silenceremove — no upload.
- [Vocal remover](https://www.safepaper.app/audio/vocal-remover): Karaoke-style center-channel cancellation to reduce lead vocals — a fast, local stem approximation.
- [Spectrogram](https://www.safepaper.app/audio/spectrogram): Render a frequency-over-time spectrogram from any audio file with the Web Audio API.
- [Loudness meter](https://www.safepaper.app/audio/loudness-meter): Measure integrated loudness (approx. LUFS) and peak dBFS with a local waveform view.
- [Transcribe](https://www.safepaper.app/audio/transcribe): Transcribe speech to text and export SRT / VTT with on-device Whisper. Audio never uploads.
- [Format convert](https://www.safepaper.app/audio/convert): Convert between MP3, WAV, FLAC, OGG, and M4A with adjustable bitrate — locally with FFmpeg.

Each tool also has a Markdown mirror at its URL plus `.md` (for example https://www.safepaper.app/audio/trim-audio.md).

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Canonical HTML: https://www.safepaper.app/audio
Markdown: https://www.safepaper.app/audio.md

There is no upload endpoint — your files are processed in this browser tab. Open your network tab and check.